The present invention relates to backup processing for performing backup of data used in an information processing device. More specifically, the invention relates to a technology that is effective when applied to the backup processing, which facilitates estimation of backup processing time and recovery processing time.
Conventionally, when performing backup of data used in information processing devices, a differential backup method is employed for reducing the amount of the backup. For managing a difference of data before and after a change, there is provided a method that uses a differential bitmap. In a backup processing method that uses this differential bitmap, a differential backup or a full backup is performed according to the number of updated bits marked on the differential bitmap (refer to JP-A-7-84728, for example).